Nowadays, the smart home market is in full swing, and the popularity of this market is remarkably attributed to control of household appliances such as television (TV) sets and air conditioners by mobile phones. For this reason, smart home manufacturers need to replicate traditional remote controls for such household appliances like TV sets and air conditioners in order to allow remote or local control.
However, existing controllers available at the marketplace from these manufacturers usually are equipped with WiFi, ZigBee or other wireless communication modules which significantly differ from the traditional remote controls in terms of circuit structure and have much more complex internal electromagnetic environments. Sampling of IR waveforms for traditional remote controls always suffers from many interference levels which may lead to failure in replication of such waveforms by controller MCUs and hence in control of the household appliances.
Remote control codes for TV sets are relatively simple and with relatively open protocols. Therefore, interference with such codes can be circumvented by software approaches using known IR control protocols. However, the replication of control waveforms for air conditioners has been a challenge in this industry, because their lengths are much longer than those of waveforms for remote control TV sets and different air conditioner manufacturers would use their own unique waveform structures for control. All conventional smart home controllers employ an I/O interface of the MCU for all sampling operations. As a result, the interference levels cannot be removed, leading to a very low success rate of waveform learning and seriously affecting the development progress and subsequent user experience.
Existing methods for interference removal are simple and crude, and they cannot accurately locate abnormal levels. That is, they cannot identify which level is abnormal or which level with short length is abnormal. They can only identify burred levels that are substantially consistent with normal levels as interference and apply manual interventions thereto. In addition, when a lot of burred levels occur, the method will be unable to identify and correct the abnormal levels.
At present, most manufacturers adopt transmission methods for low-rate wireless transmission, such as those based on ZigBee, BT and the like. However, remote controls for Japanese air conditioners usually use very long remote control codes, typically of 500 MS or more. Obviously, the low-rate transmission protocols used in the conventional sampling methods are incapable of transmitting such codes.